I think that you could also set this up as a dual screen system, if your laptop graphics card/chip is powerful enough to handle it (given that the new monitor is 1920x1200), which it might not be. What is the laptop graphics card/chip (and does it have dedicated RAM or does it share system RAM) ?

You could try googling setup dual monitor on laptop and see what that returns. This is just one of the hits, http://www.ehow.com/how_5727567_set-laptop-display-multiple-monitors.html.